I am using a DVI-to-HDMI cable to connect the video (on-board Radeon 3000) to the monitor (DVI at back of PC, to HDMI (LG) monitor).
Radio interference began to occur with a scanner radio after a few weeks of using such a cable. When the first cable caused the interference, I purchased what I believed was a better DVI-HDMI cable (Monoprice, with ferrite cores). After a week, the interference (while using the new cable) has returned. The scanner radio (portable, walkie-talkie size) is in the same room, but on the other side.
The original cable caused interference when on screenshots.debian.net. Once I moved off that page to another browser tab, closed the browser, or turned off the monitor, the interference immediately went away. With the second video cable, s.d.n. was fine, but got interference on another web page where I was viewing a large (~150 pages) PDF in the browser (Chromium). Again, moving off that tab caused the radio interference to stop. The interference also occurred when using Firefox on the same web sites.
I have a second monitor (Samsung) which I have not yet tried on this PC to see if the interference remains or disappears.
I then reduced the monitor resolution in LXQt from the default (1920x1080) to 1690x1050 and applied it, which immediately stopped the interference, but once I rebooted the system, the monitor resolution was back to 1920x1080.
The only other video option on this PC is VGA, which never caused interference. I currently cannot use an x1 video card in the PC, because the current (OEM) power supply at 250W would not be able to handle it, cards I’ve found online require a minimum 300W power supply.
Until I can find a resolution to the radio interference, is there a way to keep the monitor resolution persistent between sessions? If I find a resolution, then I will return the resolution to the default.
The two scanner frequencies where the interference (static) is occurring, are in the 150MHz band, if this helps.
Thank you in advance.
EDIT: The scanner was moved a few feet further away from where it had previously been and all is quiet, no interference.